An example :-

Please note that structure ZSTOCK is a custom table and iline looks as follow :-

data: iline type table of zstock with header line.
data: gt_fieldcat         type slis_t_fieldcat_alv.

  perform setup-fieldcatalog using gt_fieldcat[].

form setup-fieldcatalog using _fieldcat type slis_t_fieldcat_alv.
  data: ls_fieldcat type slis_fieldcat_alv.

  call function 'REUSE_ALV_FIELDCATALOG_MERGE'
       exporting
            i_internal_tabname = 'ILINE'
            i_structure_name   = 'ZSTOCK'
       changing
            ct_fieldcat        = _fieldcat.

  loop at _fieldcat into ls_fieldcat.
    case ls_fieldcat-fieldname.
      when 'DEPT'.
        ls_fieldcat-no_out    = 'X'.
       when 'DESCR'.
        ls_fieldcat-no_out    = 'X'.
      when 'GOOD_PRD'.
        ls_fieldcat-do_sum    = 'X'.
    endcase.

    modify _fieldcat from ls_fieldcat.
  endloop.

endform.                    " FIELDCATALOG
 

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